在初始化时使用 attr_accessor 设置 ruby​​ 2.0 关键字参数 [英] Set ruby 2.0 keyword arguments with attr_accessor on initialize

问题描述

如何动态设置而不必全部编写相同的代码.

How can I dynamically set without having to write the same code all over.

现在的代码是这样的:

def initialize(keywords: keywords, title: title, url: url, adsetting: adsetting)
  self.keywords = keywords
  self.title = title
  self.url = url
  self.adsetting = adsetting
end

如果列表变长，这很快就会失控.

If the list gets longer this quickly gets out of hand.

在 ruby​​ 1.9 中，我只需将哈希值传递给该方法.像这样:

With ruby 1.9 I'd just pass a hash to the method. Like this:

def initialize(args)
  args.each do |k,v|
    instance_variable_set("@#{k}", v) unless v.nil?
  end
end

但我更喜欢使用 Ruby 2.0 关键字参数.可以实现类似的目标吗?

def initialize(keywords: keywords, title: title, url: url, adsetting: adsetting)
  args.each do |k,v|
    instance_variable_set("@#{k}", v) unless v.nil?
  end
end

推荐答案

def initialize(keywords: nil, title: nil, url: nil, adsetting: nil)
  local_variables.each do |k|
    v = eval(k.to_s)
    instance_variable_set("@#{k}", v) unless v.nil?
  end
end

或遵循 John Ledbetter 和 Cary Swoveland 的建议:

or following John Ledbetter and Cary Swoveland's suggestion:

def initialize(keywords: nil, title: nil, url: nil, adsetting: nil)
  method(__method__).parameters.each do |type, k|
    next unless type == :key
    v = eval(k.to_s)
    instance_variable_set("@#{k}", v) unless v.nil?
  end
end

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